<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>修改样式</title>
    <style>
        section {
            padding: 10px;
        }

        .blue {
            color: blue;
        }

        .red {
            color: red;
        }
    </style>
</head>
<body>
    <h1>修改样式</h1>
    <section>
        <div class="content" style="color: red;">
            <a class="blue" href="http://ke.qq.com/">腾讯课堂</a>
        </div>
        <ul>
            <li>style</li>
            <li>class</li>
            <ul>
                <li>classList</li>
            </ul>
        </ul>
    </section>
</body>
</html>